Category 4 Hurricane Eta was pummeling Northeastern Nicaragua as its eyewall meandered just offshore Tuesday afternoon, ahead of what could be days of flooding in parts of Central America, the US National Hurricane Center said.

By noon Tuesday (1 p.m. ET), the storm's eyewall was closely approaching Nicaragua's Caribbean shore roughly 20 miles South-southeast of the city of Puerto Cabezas, with maximum sustained winds of 140 mph, the NHC said.

"Catastrophic wind damage" is expected when landfall happens on Nicaragua's Caribbean coast later Tuesday afternoon, the NHC said. Storm bands already were pulling roofs off houses and knocking down trees Tuesday morning in Puerto Cabezas, a city in one of Nicaragua's poorest regions, Reuters reported.

The news outlet cited Guillermo Gonzalez, the chief of the nation's disaster management agency."We're really afraid. There are fallen poles, there's flooding, roofs torn off," Puerto Cabezas resident Carmen Enriquez said Tuesday morning, according to Reuters.

To the North, homes also were being flooded Tuesday morning in Lancetilla, Honduras, amid heavy rains, pictures distributed by Getty Images show.

A hurricane warning was in effect Tuesday for a roughly 150-mile stretch of Nicaraguan coastline, from the Honduras/Nicaragua border South to Sandy Bay Sirpi on East-central Nicaragua's Caribbean coast.

Dangerous storm surge of up to 21 feet above normal tide also could crash onshore in parts of Nicaragua, Central America's poorest nation, the NHC said. The storm could deliver life-threatening conditions in Nicaragua and other Central American nations for days, including nearly 3 feet of rain in isolated parts of Nicaragua and Honduras through this week, the NHC said.

"This rainfall will lead to catastrophic, life-threatening flash flooding and river flooding, along with landslides in areas of higher terrain of Central America," the NHC said.

The current forecast has the storm meandering the mountains of Nicaragua and Honduras before heading North toward Belize as a depression by Friday. The track and intensity of the storm remains uncertain after Friday.The storm has the potential to be one of the worst flooding events Nicaragua has seen since Hurricane Mitch in 1998, which killed more than 10,000 people.

Torrential rain expected across Central America

Torrential rain, and resulting flooding and landslides, are expected to be among the main threats. The wind and storm surge threat should diminish throughout Tuesday, but the rain will last well into the week.

Rain forecasts through Sunday morning, according to the NHC:

• Much of Nicaragua and Honduras: Generally 15-25 inches, with isolated amounts up to 35 inches. • Eastern Guatemala and Belize: Generally 10-20 inches, with isolated amounts up to 25 inches. • Parts of Panama and Costa Rica: Generally 10-15 inches, with isolated amounts up to 25 inches. • El Salvador and Southeastern Mexico: Generally 5-10 inches, with isolated amounts up to 15 inches. • Jamaica, southern Haiti, and the Cayman Islands: Generally 3-5 additional inches, with isolated storm totals over 15 inches.

The slow-moving and rapidly intensifying storm -- its sustained wind speed more than doubled over the Caribbean from Sunday evening to Monday evening -- is the latest in an active Atlantic hurricane season. As the 28th named storm in the Atlantic this season, it ties the record for the number of named storms in a single season set back in 2005.